Matter.js 禁用不同复合材料之间的碰撞

Question

我正在尝试使用 "Matter.js body documentation" 中描述的碰撞过滤。但是，对于我的项目，我需要禁用不同复合对象之间的碰撞。所以只有在同一个复合体中的物体才会发生碰撞。我计划拥有超过 32 个复合材料（32 是 Matter.js 提供的最大碰撞类别数量）。我将如何实现这一目标？

// module aliases
var Engine = Matter.Engine,
    Render = Matter.Render,
    World = Matter.World,
    Bodies = Matter.Bodies,
    Body = Matter.Body,
    Vector = Matter.Vector,
    Composite = Matter.Composite,
    Constraint = Matter.Constraint,
    MouseConstraint = Matter.MouseConstraint;

// create an engine
var engine = Engine.create();

// create a renderer
var container = document.getElementById("container");
var canvas = document.getElementById("maincanvas");

var render = Render.create({
    element: container,
    canvas: canvas,
    engine: engine,
    options: {
        height: 400,
        width: 400,
        wireframes: false
    }
});

// This makes collision much easier to test
engine.world.gravity = {x:0, y:0};

// Add a mouseconstraint to test
var mc = MouseConstraint.create(engine, {
    element: render.canvas
});
Composite.add(engine.world, mc);

var bodies1 = []
var bodies2 = []
var xpos = 30
var ypos = 30
for (var i = 0; i < 5; i++){
    bodies1.push(Bodies.circle(xpos, ypos, 10, {
        collisionFilter: {
            group:-1
        },
        render: {
            fillStyle: "blue"
        }
    })
    );
    xpos += 30;
}
for (var i = 0; i < 5; i++){
    bodies2.push(Bodies.circle(xpos, ypos, 10, {
        collisionFilter: {
            group:-1
        },
        render: {
            fillStyle: "red"
        }
    })
    );
    xpos += 30;
}

var composite1 = Composite.create();
Composite.add(composite1, bodies1);
var composite2 = Composite.create();
Composite.add(composite2, bodies2);

Composite.add(engine.world, [composite1, composite2]);

Engine.run(engine);
Render.run(render);

这样我就可以禁用复合材料之间的碰撞，但这也会禁用碰撞 'inside' 复合材料。我可以用 collisionFilter.category 系统做到这一点，但它如何处理超过 32 个复合材料？

Answer 1

不支持复合级别的碰撞过滤，您需要在主体级别进行处理。为了使其更易于管理，只需创建一些复合辅助函数，例如compositeSetCollisionFilter(composite, filter) 并遍历 Composite.allBodies(composite).

关于32个类别的限制，这是由于bitwise implementation (for performance supposedly, though I doubt it matters much in reality). I've raised an issue on the project about reconsidering this。

如果您将 Matter.Detector.canCollide(filterA, filterB) 替换为您自己的可以比较两个 body.collisionFilter 对象的函数，那么现在有一种方法可以获得更多。有了这个，您可以为 body.collisionFilter 个对象使用任何您喜欢的方案。

Matter.js 禁用不同复合材料之间的碰撞

Matter.js disable collision between different composites

javascript

physics-engine

matter.js